Optically active iridium complexes, their preparation and their use in transfer hydrogenation

ABSTRACT

Optically active iridium complexes of the formula I and mixtures of the diastereomers ##STR1## in which R 1  and R&#39; are H and A is a radical of the formula II, IIa or IIb ##STR2## or R 1  and R&#39; represent a bond and A is a radical of the formula IIc ##STR3## in which R 2  is --H or --CH 3 , X.sup.⊖ is an anion of an inorganic or organic acid, Y and Z are each ethylene, or Y and Z together represent an open-chain or cyclic diene having 6-10 C atoms, whose double bonds are separated by one or two C atoms, and R is a hydrocarbon radical having at least one chiral C atom or a hydrocarbon radical having at least one hetero atom and at least one chiral C atom, or A is a radical of the formula II, IIa or IIb and R is phenyl, naphthyl, 2-methylphen-1-yl or 2,6-dimethylphen-1-yl. The complexes are suitable as enantioselective catalysts.

The present invention relates to optically active cationic iridium(I)complexes having an asymmetric secondary amine ligand and a dieneligand, a process for their preparation, and their use as homogeneousenantioselective catalysts.

G. Zassinovich et al., in Journal of Organometallic Chemistry, 222,pages 323-329 (1981), describe cationic iridium(I) complexes having a1,5-cyclooctadiene ligand and a 2-pyridinaldimine ligand which issubstituted at the imine N atom by optically active α-phenylethyl or3-pinanemethyl. They act as enantioselective homogeneous catalysts inthe transfer hydrogenation of prochiral ketones with isopropanol.Although high yields are achieved in the reaction, the optical yield(enantiomeric excess) is relatively low.

H. Brunner et al., in Chem. Ber., 117, pages 1330-1354 (1984), describecationic rhodium(I) complexes having a cycloocta-1,5-diene ligand and anasymmetric α-(secondary aminomethyl)-pyridine ligand as homogeneouscatalysts for the enantioselective hydrosilylation of prochiral ketones.

The invention relates to optically active iridium complexes of theformula I and mixtures of the diastereomers. ##STR4## in which R¹ and R'are H and A is a radical of the formula II, IIa or IIb ##STR5## or R¹and R' represent a bond and A is a radical of the formula IIc ##STR6##in which R² is --H or --CH₃, X⁻ is an anion of an inorganic or organicacid, Y and Z are each ethylene, or Y and Z together represent anopen-chain or cyclic diene having 6-10 C atoms, whose double bonds areseparated by one or two C atoms; and R is a hydrocarbon radical havingat least one chiral C atom or a hydrocarbon radical having at least onehetero atom and at least one chiral C atom, or A is a radical of theformula II, IIa or IIb and R is phenyl, naphthyl, 2-methylphen-1-yl or2,6-dimethylphen-1-yl.

Optically active means that at least one chiral C atom predominantly hasthe S or R configuration.

X.sup.⊖ as an anion of a monobasic inorganic or organic acid can be, forexample, F.sup.⊖, Cl.sup.⊖, Br.sup.⊖, I.sup.⊖, ClO₄.sup.⊖, NO₃.sup.⊖,BrO₃.sup.⊖, HSO₄.sup.⊖, H₂ PO₃.sup.⊖, H₂ PO₄.sup.⊖, BF₄.sup.⊖,B(phenyl)₄.sup.⊖, PF₆.sup.⊖, SbF₆.sup.⊖, AsF₆.sup.⊖, SbCl₆.sup.⊖, SbCl₅F.sup.⊖, HCOO.sup.⊖, CH₃ COO.sup.⊖, CCl₃ COO.sup.⊖, CF₃ COO.sup.⊖, CH₃SO₃.sup.⊖, CCl₃ SO₃.sup.⊖, CF₃ SO₃.sup.⊖, phenyl-SO₃.sup.⊖ orp-toluyl-SO₃.sup.⊖. In a preferred embodiment, X.sup.⊖ is BF₄.sup.⊖,ClO₄.sup.⊖, CF₃ SO₃.sup.⊖ or PF₆.sup.⊖.

Y and Z are each preferably ethylene, or Y and Z together are preferablya diene having 6 to 8 C atoms, whose diene groups are bonded inparticular via 2 C atoms. In a preferred embodiment, Y and Z togetherare 1,5-cyclooctadiene, norbornadiene or 1,5-hexadiene.

A preferred subgroup of iridium complexes comprises those of the formulaI, in which R is a radical of the formula III ##STR7## in which R³, R⁴and R⁵ differ from one another when they do not contain at least 1chiral C atom, and are a hydrogen atom, C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy,cycloalkyl having 5 to 7 ring C atoms which is unsubstituted orsubstituted by C₁ -C₄ -alkyl or phenyl, cycloalkylalkyl which isunsubstituted or substituted by C₁ -C₄ -alkyl or phenyl and has 5 to 7ring C atoms and 1 or 2 C atoms in the alkylene group, phenyl, naphthyl,benzyl or β-phenylethyl; or R⁴ and R⁵ together are C₁ -C₄-alkyl-substituted or phenyl-substituted linear C₄ - or C₅ -alkylene,C₄ - or C₅ -oxaalkylene or C₅ -dioxaalkylene having at least one chiralC atom. In a preferred embodiment, R³ in formula III is a hydrogen atom.

C₁ -C₄ -alkyl and C₁ -C₄ -alkoxy radicals may be methyl, ethyl,n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl and the correspondingalkoxy radicals. Alkyl radicals R³, R⁴ and R⁵ are preferably methyl orethyl and alkoxy radicals R³, R⁴ and R⁵ are preferably methoxy.Cycloalkyl radicals R³ to R⁵ are preferably cyclopentyl, cycloheptyl andin particular cyclohexyl. Cycloalkylalkyl radicals R² to R⁴ arepreferably cyclohexylmethyl. R³ and R⁴ together as C₃ -C₄ -oxaalkyleneare preferably 2-oxabutylene or 2- or 3-oxapentylene and as C₃-dioxaalkylene are preferably 2,4-dioxapentylene. C₁ -C₄ -alkyl as asubstituent for R³ to R⁵ can be methyl, ethyl, n-propyl, isopropyl orbutyl. Pref-erred substituents are methyl and phenyl.

A preferred subgroup of iridium complexes of the formula I comprisesthose in which, in formula III, R³ is H, R⁴ is C₁ -C₄ -alkyl, C₁ -C₄-alkoxy or phenyl and R⁵ is phenyl, benzyl or naphthyl, and R³ and R⁴are not both phenyl; or R³ and R⁵ are each H and R⁴ corresponds to theformula ##STR8## or the group --CR³ R⁴ R⁵ corresponds to the formula##STR9## or R³ is H and R⁴ and R⁵ together are pentamethylene which issubstituted in the 2-position by C₁ -C₄ -alkyl, or are2,4-dioxapentylene which is substituted in the 1- and/or 3-position byC₁ -C₄ -alkyl or phenyl.

Another embodiment of preferred iridium complexes comprises those inwhich the radical of the formula III corresponds to the radicals##STR10## in which R⁶ is methyl or phenyl, R⁷ is methyl or phenyl and R⁸and R⁹ are methyl, or R⁸ is H and R⁹ is phenyl.

Iridium complexes of the formula I, in which R¹ and R' are a bond and Ais a radical of the formula IIc, in which R² is methyl and R correspondsto the radicals ##STR11## in which R⁷ is phenyl, R¹⁰ is phenyl ornaphthyl and R¹¹ is H, or R¹⁰ and R¹¹ are phenyl, are particularlypreferred.

Another preferred subgroup comprises iridium complexes of the formula I,in which R¹ and R' are a bond and A is a radical of the formula IIc, inwhich R² is H and R is 2-methylcyclohex-1-yl, 2-phenylcyclohex-1-yl##STR12## in which R⁷ is phenyl and R¹² and R¹³ are --CH₃, or R¹² is Hand R¹³ is phenyl.

In a preferred embodiment, the iridium complexes of the formula I arethose in which R¹ and R' are H and A is a radical of the formula II andR is a radical ##STR13## in which R¹⁰ and R¹¹ are phenyl, or R¹⁰ isphenyl or naphthyl and R¹¹ is H or R¹⁰ is methyl and R¹¹ is phenyl.

Preferred iridium complexes of the formula I in which R¹ and R' are eachH and A is a radical of the formula IIa are those in which R is phenyl,2-methylphen-1-yl or 2,6-dimethylphen-1-yl.

Other preferred iridium complexes of the formula I are those in whichX.sup.⊖ is BF₄.sup.⊖ and Y and Z together are 1,5-cyclooctadiene.

The iridium complexes of the formula I can be obtained by processeswhich are known per se [see Inorganica Chimica Acta 73 (1983), pages275-279], by reacting [(acetonitrile)₂ (YZ)]IrX with an optically activesecondary amine of the formula IV ##STR14## in which Y, Z, X, A, R, R¹and R' have the meanings stated in claim 1. The preparation of theacetonitrile complex is likewise described there. The complexes[IrCl(YZ)]₂ used for the preparation of the acetonitrile complex areobtainable, for example, by the reaction ofdichlorotetrakis(alkene)diiridium(I) (alkene: for example, cyclooctene)with ethylene or a diene YZ.

The reactions are carried out in general at temperatures of -10° to 30°C. in an inert solvent and in the absence of oxygen and of moisture.Examples of suitable inert solvents are hydrocarbons, such as benzene,toluene, xylene, petroleum ether, hexane, cyclohexane andmethylcyclohexane; and ethers, such as, for example, diethyl ether,dibutyl ether, tetrahydrofuran and dioxane, as well as halogenatedhydrocarbons, for example chloroform, methylene chloride andchlorobenzene. To prepare salts of the formula I with anions ofmonobasic inorganic or organic acids, the salts of the formula I can bereacted, either directly after the reaction or after isolation andpurification and redissolution in polar solvents (for example alcohols,ethers or ketones, with or without the addition of water), with analkali metal salt M.sup.⊕ X'.sup.⊖ and then isolated. X'.sup.⊖ is ananion, differing from X.sup.⊖ of a monobasic inorganic or organic acid,and M.sup.⊕ is preferably sodium. The iridium complexes according to theinvention are crystalline and can be isolated by filtration and purifiedby recrystallization. Some of the optically active secondary amines ofthe formula IV are known or are commercially available, or they can beprepared by known processes. Amines of the formula IV in which A is aradical of the formula IIc and R¹ and R' are a bond are obtained in asimple manner by catalytic hydrogenation of the corresponding amines,for example ##STR15##

The pyridinaldimines of the formula V are known or can be obtained in amanner known per se by reacting unsubstituted or methyl-substituted2-pyridinealdehyde with an amine RNH₂. Advantageously, purestereoisomers of the amines RNH₂ are used, so that pure stereoisomers ofthe formula V are obtained. However, it is also possible to useracemates and subsequently resolve the resulting racemates of theformula V by well established methods.

Stereoisomers of the amines RNH₂ are known, and some of them arecommercially available or can be prepared by known processes. Examplesof such amines are: (R)-2-aminobutane, (R)-1-phenylethylamine,(S)-1-phenylethylamine, (R)-1-(α-naphthylethyl)-amine,(S)-2-amino-3-phenylpropane, (R)-1,2-diphenylethylamine, (S)-alaninol,(S)-phenylalaninol, (4S,5S)-5-amino-2,2-dimethyl-4-phenyl-1,3-dioxane,(S)-2-amino-1-methoxy-3-phenyl-propane, (R)-bornylamine,(R)-3-aminomethylpinane, (+)-dehydroabietylamine,(2R,4S,5S)-(+)-5-amino-2,4-diphenyl-1,3-dioxane [Chem. Ber. 113, pages710-721 (1980)], (1S,2R)-(-)-2-methylcyclohexylamine [Chem. Ber. 117,pages 2076-2098 (1984)] and (1S,2S)-(+)-2-phenylcyclohexylamine [Chem.Ber. 117, pages 2076-2098 (1984)].

Optically active secondary amines of the formula IV, in which A is aradical of the formula IIa and R¹ and R' are H, can likewise be obtainedfrom the imines of the formula V by catalytic hydrogenation with, forexample, PtO₂ as a catalyst.

Optically active secondary amines of the formula IV, in which A is aradical of the formula II, IIa or IIb and R¹ and R' are H, can beprepared by the following process (Z' is --COOCH₂ C₆ H₅ and * representspredominantly S or predominantly R configuration, the radical R in theamine RNH₂ containing no chiral C atom or at least one chiral C atom):##STR16## 2-piperidine-, 2-pyrrolidine- and 2-indolinecarboxylic acidand their stereoisomers are known. Examples of suitable amines R--NH₂are aniline, 1-amino-3-methylbenzene, 1-amino-2,6-dimethylbenzene,α-naphthylamine, (R)-1-phenylethylamine, (S)-1-phenylethylamine and(R)-1,2-diphenylethylamine.

The invention further relates to the use of the iridium complexesaccording to the invention as enantioselective homogeneous catalysts, inparticular for the transfer hydrogenation of prochiral ketones withsecondary alcohols. A particularly suitable secondary alcohol isisopropanol. The reaction is advantageously carried out in the absenceof oxygen at elevated temperature, for example 40°-120° C. The secondaryalcohol used is advantageously employed as the solvent. The amount ofcatalyst is preferably 10⁻² to 10⁻⁵ mol/l, relative to the reactionvolume. The reaction is preferably carried out in the presence of abase, in particular NaOH.

The Examples which follow illustrate the invention in more detail. Theenantiomeric excess (ee) is determined according to Mosher [J. Org.Chem. 34, page 2543 (1969)].

EXAMPLES 1-9

0.469 g (1.0 mmol) of bis-(acetonitrile)-(cycloocta-1,5-diene)iridiumtetrafluoroborate is dissolved in 15 ml of dichlormethane under argonprotective gas. A solution of 5 ml of dichloromethane and 1.0 mmol ofthe N-substituted 2-(aminomethyl)-6-methylpyridine(N,N ligand) is addeddropwise at room temperature and while stirring. After 1 hour, thereaction mixture is evaporated down to about one third of its volume,under about 600 Pa. If the product does not crystallize spontaneously,60 ml of diethyl ether are added, the product being obtained as a solidprecipitate in the course of 3 hours. The finely pulverulent product isfiltered off under suction under argon, washed three times with diethylether and dried for about 16 hours under 0.1 Pa. The yields are 80% oftheory. The colour and the elemental analysis of the complexes obtainedare listed in Table 1.

                                      TABLE 1                                     __________________________________________________________________________     Example no.                                                                          Complex                                                                                 ##STR17##           Colour  Elemental analysis [% by                                                     weight]                          __________________________________________________________________________    1      [Ir(N,N)(COD)]BF.sub.4                                                                   ##STR18##          yellow  Found: C 49.5; H 5.02; N                                                      4.10; Ir 27.5 Calc.: C                                                        50.51; H 4.97; N 4.06; Ir                                                     27.87                            2      "                                                                                        ##STR19##          orange  Found: C 44.23; H 5.27; N                                                     4.37; Ir 28.5 Calc.: C                                                        44.38; H 5.02; N 4.50; Ir                                                     30.87                            3      "                                                                                        ##STR20##          orange red                                                                            Found: C 46.33; H 4.96; N                                                     4.01; Ir 27.2 Calc.: C                                                        46.35; H 5.19; N 4.00; Ir                                                     27.47                            4      "                                                                                        ##STR21##          dark yellow                                                                           Found: C 43.02; H 4.89; N                                                     3.76; Ir 25.4 Calc.: C                                                        43.03; H 5.62; N 3.72; Ir                                                     25.5                             5      [Ir(N,N)(COD)]BF.sub.4                                                                   ##STR22##          yellow  Found: C 44.56; H 5.11; N                                                     4.64; Ir 28.7 Calc.: C                                                        44.45; H 5.37; N 4.15; Ir                                                     28.45                            6      "                                                                                        ##STR23##          pale yellow                                                                           Found: C 44.73; H 5.89; N                                                     4.55; Ir 27.7 Calc: C 44.05;                                                  H 6.21; N 4.11; Ir 28.2          7      "                                                                                        ##STR24##          pale beige                                                                            Found: C 46.11; H 6.01; N                                                     4.32 Calc.: C 46.08; H 6.25;                                                   4.13                            8      [Ir(N,N)(COD)]BF.sub.4                                                                   ##STR25##          yellowish green                                                                       Found: C 48.15; H 4.98; N                                                     3.55; Ir 24.9 Calc.: C                                                        48.64; H 4.88; N 3.66; Ir                                                     25.1                             9      "                                                                                        ##STR26##          yellow  Found: C 42.20; H 5.56; N                                                     4.52; Ir 29.6 Calc.: C                                                        42.38; H 5.82; N 4.44; Ir                                                     30.82                            __________________________________________________________________________     COD is cycloocta1,5-diene                                                

EXAMPLES 10-19

The N-substituted 2-(aminomethyl)pyridines described in detail in Table2 are reacted with bis-(acetonitrile)(cycloocta-1,5-diene)iridiumtetrafluoroborate analogously to Examples 1-9. After analogous workingup, the complexes listed in Table 2 are obtained.

                                      TABLE 2                                     __________________________________________________________________________     Example no.                                                                           Complex                                                                                ##STR27##           Colour   Elemental analysis [% by                                                     weight]                         __________________________________________________________________________    10     [Ir(N,N)(COD)]BF.sub.4                                                                   ##STR28##          yellowish beige                                                                        Found: C 44.65; H 5.85; N                                                     4.29; Ir 28.5 Calc.: C                                                        44.38; H 5.90; N 4.31; Ir                                                     29.5                            11     "                                                                                        ##STR29##          yellowish beige                                                                        Found: C 49.16; H 4.89; N                                                     4.10; Ir 26.2; F 10.27                                                        Calc.: C 49.18; H 4.54; N                                                     3.82; Ir 26.24; F 10.37         12     "                                                                                        ##STR30##          yellowish orange                                                                       Found: C 45.67; H 4.66; N                                                     4.02; Ir 26.0 Calc.: C                                                        45.62; H 4.86; N 4.09; Ir                                                     28.08                           13     "                                                                                        ##STR31##          yellow   Found: C 45.92; H 5.37; N                                                     4.37 Calc.: C 45.79; H                                                        5.44;  N 4.45                   14     [Ir(N,N)(COD)]BF.sub.4                                                                   ##STR32##          orange   Found: C 42.1; H 5.5; N                                                       4.8; Ir 31.4 Calc.: C                                                         41.45; H 5.47; N 4.6; Ir                                                      31.59                           15     "                                                                                        ##STR33##          beige    Found: C 37.92; H 5.23; N                                                     4.73; Ir 30.6 Calc.: C                                                        37.94; H 5.70; N 4.66; Ir                                                     31.9                            16     "                                                                                        ##STR34##          orange   Found: C 49.24; H 4.72; N                                                     4.26; Ir 28.2 Calc: C                                                         49.78; H 4.77; N 4.15; Ir                                                     28.45                           17     "                                                                                        ##STR35##          yellowish orange                                                                       Found: C 44.61; H 4.78 N                                                      4.47; Ir 30.1 Calc.: C                                                        45.03; H 4.93; N 4.57; Ir                                                     3.13                            18     [Ir(N,N)(COD)]BF.sub.4                                                                   ##STR36##          orange   Found: C 43.66; H 4.88; N                                                     4.52; Ir 30.5 Calc.: C                                                        43.43: H 4.80; N 4.60; Ir                                                     31.5                            19     "                                                                                        ##STR37##          orange   Found: C 45.40; H 5.97; N                                                     4.16; Ir 29.1 Calc.: C                                                        45.25; H 6.08; N 4.22; Ir                                                     29.0                            __________________________________________________________________________

EXAMPLES 20-26

The N-substituted 2-(aminomethyl)-piperidines described in detail inTable 3 are reacted with bis-(acetonitrile)(cycloocta-1,5-diene)iridiumtetrafluoroborate analogously to Examples 1-9. After analogous workingup, the complexes listed in Table 3 are obtained.

EXAMPLES 27-30

The N-substituted 2-(aminomethyl)-pyrrolidines listed in Table 4 arereacted with bis-(acetonitrile)(cycloocta-1,5-diene)iridiumtetrafluoroborate analogously to Examples 1-9. After analogous workingup, the complexes listed in Table 4 are obtained.

EXAMPLES 31-33

The N,N ligands listed in Table 5 are reacted withbis-(acetonitrile)(cycloocta-1,5-diene)iridium tetrafluoroborateanalogously to Examples 1-9. After analogous working up, the complexeslisted in Table 5 are obtained.

                                      TABLE 3                                     __________________________________________________________________________                      ##STR38##                    Elemental analysis             Example no.                                                                          Complex   A (absolute configuration).sup.1                                                                      Colour                                                                             [% by weight]                   __________________________________________________________________________    20     [Ir(N,N)(COD)]BF.sub.4                                                                   ##STR39##          (S) green                                                                              Found: Calc.:                                                                     C 40.64; H 5.35; N                                                            4.82; Ir 31.9 C 40.34;                                                        H 5.42; N 4.70; Ir                                                            32.28                       21     "                                                                                        ##STR40##          (R,R)                                                                             beige                                                                              Found: Calc.:                                                                     C 46.80; H 5.57; N                                                            3.98; Ir 26.6 C 46.86;                                                        H 5.90; N 3.90; Ir                                                            26.8                        22     "                                                                                        ##STR41##          (R,R)                                                                             pale beige                                                                         Found: Calc:                                                                      C 42.82; H 5.53; N                                                            4.56; Ir 31.1 C 42.38;                                                        H 5.82; N 4.49; Ir                                                            30.82                       23     "                                                                                        ##STR42##          (S,R)                                                                             yellow                                                                             Found: Calc.:                                                                     C 41.56; H 5.64; N                                                            4.43; F 11.74 C 41.19;                                                        H 5.97; N 4.37; F                                                             11.85                       24     [Ir(N,N)(COD)]BF.sub.4                                                                   ##STR43##          (R,S)                                                                             greenish yellow                                                                    Found: Calc.:                                                                     C 42.68; H 5.43; N                                                            4.64; Ir 30.1 C 42.38;                                                        H 5.82; N 4.49; Ir                                                            30.82                                        (diastereomer mixture:                                                        R,R: S,R =  43:57)                                           25     "                                                                                        ##STR44##              beige                                                                              Found: Calc.:                                                                     C 43.41; H 5.67; N                                                            4.63; Ir 30.1 C 43.64;                                                        H 5.66; N 4.63; Ir                                                            31.74                                        (diastereomer mixture:                                                        R,S: S,S =  42:58)                                           26     [Ir(N,N)(COD)]BF.sub.4                                                                   ##STR45##              beige orange                                                                       Found: Calc.:                                                                     C 46.41; H 5.34; N                                                            3.53; Ir 24.4 C 46.43;                                                        H 5.72; N 3.61; Ir                                                            24.78                                        (diastereomer mixture:                                                        S,4S,5S R,4S,5S ˜ 1:1)                                 __________________________________________________________________________     (1) The first symbol (R or S) relates to the 2position in the piperdine       ring                                                                     

                                      TABLE 4                                     __________________________________________________________________________                      ##STR46##                         Elemental analysis        Example no.                                                                          Complex   A (absolute configuration).sup.1                                                                          Colour                                                                              [% by                      __________________________________________________________________________                                                       weight]                    27     [Ir(N,N)(COD)]BF.sub.4                                                                   ##STR47##               (S)                                                                              yellow                                                                              Found: Calc.:                                                                     C 39.46; H 5.14; N                                                            4.79; Ir 33.1 C                                                               39.25; H 5.20; N                                                              4.82; Ir 33.05         28     "                                                                                        ##STR48##               (S)                                                                              lemon yellow                                                                        Found: Calc.:                                                                     C 42.52; H 5.50; N                                                            4.66; Ir 32.2 C                                                               42.64; H 5.45; N                                                              4.74; Ir 32.50         29     "                                                                                        ##STR49##               (S,S)                                                                            pale yellow                                                                         Found: Calc.:                                                                     C 40.84; H 5.42; N                                                            4.75; Ir 31.5 C                                                               41.38; H 5.62; N                                                              4.60; Ir 31.53         30     "                                                                                        ##STR50##                  yellow                                                                              Found: Calc.:                                                                     C 46.36; H 5.11; N                                                            3.90; Ir 25.2 C                                                               46.84; H 5.42; N                                                              3.77; Ir 25.85                          (S, 2R, 4S, 5S)                                              __________________________________________________________________________    Example no.                                                                          Complex   N,NLigand                   Colour                                                                              Elemental                  __________________________________________________________________________                                                       analysis                   31     [Ir(N,N)(COD)]BF.sub.4                                                                   ##STR51##                  brown Found: Calc.:                                                                     C 49.13; H 5.96; N                                                            3.94; Ir 25.8 C                                                               48.81; H 5.93; N                                                              3.93; Ir 26.0                           diastereomer mixture                                         32     "                                                                                        ##STR52##                  yellow                                                                              Found: Calc.:                                                                     C 43.80; H 5.65; N                                                            4.51; Ir 29.4 C                                                               43.54; H 5.56; N                                                              4.42; Ir 30.29                          diastereomer mixture                                         33     "                                                                                        ##STR53##                  greenish yellow                                                                     Found: Calc.:                                                                     C 44.27; H 4.90; N                                                            4.44: Ir 29.7 C                                                               43.88; H 4.80; N                                                              4.45; Ir               __________________________________________________________________________                                                           30.53                   (1) The first symbol (R or S) relates to the 2position of the pyrrolidine     ring                                                                     

EXAMPLE 34 ##STR54## 0.337 g (0.376 mmol) ofdi-μ-chlorotetrakis(cyclooctene)diiridium(I) is dissolved in 26 ml ofbenzene under argon protective gas. 2.6 ml of 1,5-hexadiene are addeddropwise at 10° C. The mixture is stirred for 1 hour, after which asolution of the diamine in 2 ml of benzene is added dropwise. Thereaction mixture is stirred for 1 hour at room temperature and thenfiltered over Celite. The product is precipitated as a beige powder when120 ml of hexane are added. It is filtered off, washed several timeswith hexane and dried for 18 hours under 0.1 Pa.

Colour: beige

Microanaylsis (formula:

    ______________________________________                                        C.sub.20 H.sub.26 N.sub.2 ClIr):                                                           C      H          N    Cl                                        ______________________________________                                        Calculated   46.01  5.02       5.37 6.79                                      Found        40.61  4.74       4.1  7.58                                      ______________________________________                                    

The product contains about 20% ofdi-μ-chlorotetrakis(cyclooctene)diiridium(I).

EXAMPLE 35 (USE EXAMPLE)

6.42 mg of the complex prepared according to Example 2 are dissolved in39.5 ml of isopropanol in the absence of oxygen (argon atmosphere).After the solution has been stirred for 1 hour at 60° C., 0.42 ml of0.1N sodium hydroxide solution is added. Stirring is continued for afurther hour at 60° C., and a solution of 39.5 ml of isopropanol and1.55 g of butyrophenone is then added in the absence of oxygen. Themolar ratio of substrate to catalyst is thus [s]/[cat.]=1000, and thecatalyst concentration is 1.33.10⁻⁴ mol/l.

After 3 hours at 60° C., the yield of 1-phenyl-1-butanol is determinedas 90.9% of theory by gas chromatography (OV 101, 120° C., isothermal).

To determine the enantiomer content according to Mosher, a sample of thereaction mixture (about 0.5 ml) is substantially freed from the solvent,and 50 μl of optically pure α-methoxy-α-trifluoromethylphenylacetylchloride and 0.25 ml of dry pyridine are added at 0° C. After 15minutes, the mixture is heated to 70° C. for 30 minutes and cooled,after which 3 ml of 10% citric acid solution are added and thediastereomeric esters are extracted with ether.

An enantiomeric excess ee of (S)-1-phenylbutanol of 54.2% is determinedby gas chromatography (capillary column CW 20, 190° C.).

EXAMPLE 36 (USE EXAMPLE)

The complex according to Example 2 is used for the catalytic,enantioselective transfer hydrogenation of isobutyrophenone, analogouslyto Example 35.

After 1 hour 45 minutes, the yield of 1-phenyl-2-methylpropanol is95.3%, and the enantiomeric excess ee is 57.3% of (S).

EXAMPLE 37 (USE EXAMPLE)

The complex according to Example 1 is used for the catalytic,enantioselective transfer hydrogenation of butyrophenone, analogously toExample 35.

After 12 hours 45 minutes, the yield of 1-phenylbutanol is 90.4%, andthe enantiomeric excess ee is 60.4% of (R).

EXAMPLE 38 (USE EXAMPLE)

The complex according to Example 12 is used for the catalytic,enantioselective transfer hydrogenation of butyrophenone, similarly toExample 35. However, the concentration conditions [S]/[cat.]=100 and[cat.]=2.10⁻³ mol/l are chosen.

After 18 hours, the yield is 78.8% of 1-phenylbutanol, and theenantiomeric excess ee is 55.3% of (S).

EXAMPLE 39 (USE EXAMPLE)

The complex according to Example 23 is used for the catalytic,enantioselective transfer hydrogenation of butyrophenone, similarly toExample 35. However, the concentration conditions [S]/[cat.]=1000 and[cat.]=1.33.10⁻⁴ mol/l are chosen.

After 20 hours, the yield is 88.8% of 1-phenylbutanol, and theenantiomeric excess ee is 60.1% of (R).

EXAMPLE 40 (USE EXAMPLE)

The complex according to Example 25 is used for the catalytic,enantioselective transfer hydrogenation of butyrophenone, similarly toExample 35. However, the concentration conditions [S]/[cat.]=1000 and[cat.]=1.33.10⁻⁴ mol/l are chosen.

After 20 hours, the yield is 45.3% of 1-phenylbutanol, and theenantiomeric excess ee is 54.1% of (S).

EXAMPLE 41 (USE EXAMPLE)

The complex according to Example 20 is used for the catalytic,enantioselective transfer hydrogenation of butyrophenone, similarly toExample 35. However, the concentration conditions [S]/[cat.]=1000 and[cat.]=1.33.10⁻¹ mol/l are chosen.

After 20 hours 30 minutes, the yield is 31.2% of 1-phenylbutanol, andthe enantiomeric excess ee is 49.3% of (R).

EXAMPLE 42 (USE EXAMPLE)

The complex according to Example 27 is used for the catalytic,enantioselective transfer hydrogenation of butyrophenone, analogously toExample 35.

After 20 hours, the yield is 39.0% of 1-phenylbutanol, and theenantiomeric excess ee is 29.2% of (R).

EXAMPLE 43 (USE EXAMPLE)

The complex according to Example 32 is used for the catalytic,enantioselective transfer hydrogenation of butyrophenone, similarly toExample 35. However, the concentration conditions [S]/[cat.]=1000 and[cat.]=1.33.10⁻⁴ mol/l are chosen.

After 2 hours, the yield is 95.0% of 1-phenylbutanol, and theenantiomeric excess ee is 60.4% of (S).

What is claimed is:
 1. An optically active iridium complex of theformula I and a mixture of the diastereomers ##STR55## in which R¹ andR' are H and A is a radical of the formula II, IIa or IIb ##STR56## orR¹ and R' represent a bond and A is a radical of the formula IIc##STR57## in which R² is --H or --CH₃, X.sup.⊖ is an anion of aninorganic or organic acid, Y and Z are each ethylene, or Y and Ztogether represent an open-chain or cyclic diene having 6-10 C atoms,whose double bonds are separated by one or two C atoms; and R is aradical of the formula III ##STR58## in which R³, R⁴ and R⁵ differ fromone another when they do not contain at least 1 chiral C atom, and are ahydrogen atom, C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, cycloalkyl having 5 to 7ring C atoms which is unsubstituted or substituted by C₁ -C₄ -alkyl orphenyl, cycloalkylalkyl which is unsubstituted or substituted by C₁ -C₄-alkyl or phenyl and has 5 to 7 ring C atoms and 1 or 2 C atoms in thealkylene group, phenyl, naphthyl, benzyl or β-phenylethyl; or R⁴ and R⁵together are C₁ -C₄ -alkyl-substituted or phenyl-substituted linear C₄ -or C₅ -alkylene, C₄ - or C₅ -oxaalkylene or C₅ -dioxaalkylene havingone, two or three chiral C atoms, or R³ and R⁵ are each H and R⁴corresponds to the formula ##STR59## or the group --CR³ R⁴ R⁵corresponds to the formula ##STR60## or A is a radical of the formulaII, IIa or IIb and R is phenyl, naphthyl, 2-methylphen-1-yl or2,6-dimethylphen-1-yl.
 2. An iridium complex of the formula I accordingto claim 1, wherein X.sup.⊖ is BF₄.sup.⊖, ClO₄.sup.⊖, CF₃ SO₃.sup.⊖ orPF₆.sup.⊖.
 3. An iridium complex of the formula I according to claim 1,wherein Y and Z together are 1,5-cyclooctadiene, norbornadiene or1,5-hexadiene.
 4. An iridium complex of the formula I according to claim1, wherein R is a radical of the formula III ##STR61## in which R³, R⁴and R⁵ differ from one another when they do not contain at least 1chiral C atom, and are a hydrogen atom, C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy,cycloalkyl having 5 to 7 ring C atoms which is unsubstituted orsubstituted by C₁ -C₄ -alkyl or phenyl, cycloalkylalkyl which isunsubstituted or substituted by C₁ -C₄ -alkyl or phenyl and has 5 to 7ring C atoms and 1 or 2 C atoms in the alkylene group, phenyl, naphthyl,benzyl or β-phenylethyl; or R⁴ and R⁵ together are C₁ -C₄-alkyl-substituted or phenyl-substituted linear C₄ - or C₅ -alkylene,C₄ - or C₅ -oxaalkylene or C₅ -dioxaalkylene having one, two or threechiral C atoms; or R³ and R⁵ are each H and R⁴ corresponds to theformula ##STR62## or the group --CR³ R⁴ R⁵ correspond to the formula##STR63##
 5. An iridium complex of the formula I according to claim 4,wherein R³ in formula III is H.
 6. An iridium complex of the formula Iaccording to claim 4, wherein, in formula III, R³ is H, R⁴ is C₁ -C₄-alkyl, C₁ -C₄ -alkoxy or phenyl and R⁵ is phenyl, benzyl or naphthyl,and R³ and R⁴ are not both phenyl; or R³ and R⁵ are each H and R⁴corresponds to the formula ##STR64## or the group --CR³ R⁴ R⁵corresponds to the formula ##STR65## or R³ is H and R⁴ and R⁵ togetherare pentamethylene which is substituted in the 2-position by C₁ -C₄-alkyl, or are 2,4-dioxapentylene which is substituted in the 1- and/or3-position by C₁ -C₄ -alkyl or phenyl.
 7. An iridium complex of theformula I according to claim 4, wherein the radical of the formula IIcorresponds to the radicals ##STR66## in which R⁶ is methyl or phenyl,R⁷ is methyl or phenyl and R⁸ and R⁹ are methyl, or R⁸ is H and R⁹ isphenyl.
 8. An iridium complex of the formula I according to claim 1,wherein R¹ and R' are a bond and A is a radical of the formula IIc, inwhich R² is methyl and R corresponds to the radicals ##STR67## in whichR⁷ is phenyl, R¹⁰ is phenyl or naphthyl and R¹¹ is H, or R¹⁰ and R¹¹ arephenyl.
 9. An iridium complex of the formula I according to claim 1,wherein R¹ and R' are a bond and A is a radical of the formula IIc, inwhich R² is H and R is 2-methylcyclohex-1-yl, 2-phenylcyclohex-1-yl##STR68## in which R⁷ is phenyl and R¹² and R¹³ are --CH₃, or R¹² is Hand R¹³ is phenyl.
 10. An iridium complex of the formula I according toclaim 1, wherein R¹ and R' are H and A is a radical of the formula IIand R is a radical ##STR69## in which R¹⁰ and R¹¹ are phenyl, or R¹⁰ isphenyl or naphthyl and R¹¹ is H, or R¹⁰ is methyl and R¹¹ is phenyl. 11.An iridium complex of the formula I according to claim 1, wherein R¹ andR' are H and A is a radical of the formula IIa, and R is phenyl,2-methylphen-1-yl or 2,6-dimethylphen-1-yl.
 12. An iridium complex ofthe formula I according to claim 1, wherein X.sup.⊖ is BF₄.sup.⊖ and Yand Z together are 1,5-cyclooctadiene.